Compositions Comprising C5 and C6 Monosaccharides

ABSTRACT

Compositions comprising C5 and C6 monosaccharides and low levels of undesirable impurities, such as compounds containing sulfur, nitrogen, or metals, are disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/649,437 filed Oct. 11, 2012, currently pending, which claims thebenefit of:

U.S. Application No. 61/581,922 filed Dec. 30, 2011;

U.S. Application No. 61/581,907 filed Dec. 30, 2011;

U.S. Application No. 61/581,878 filed Dec. 30, 2011; and

U.S. Application No. 61/581,890 filed Dec. 30, 2011;

the entire disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to compositions comprising C5and C6 monosaccharides containing maximum levels of undesirableimpurities, such as compounds containing sulfur, nitrogen, or metals,especially those processed from lignocellulosic biomass usingsupercritical, subcritical, and/or near critical fluid extraction.

BACKGROUND OF THE INVENTION

There are a number of processes for converting lignocellulosic biomassinto liquid streams of various fermentable sugars. Certain preferredprocesses are based on supercritical water (SCW) or hot compressed water(HCW) technology, which offer several advantages including highthroughputs, use of mixed feedstocks, separation of sugars, andavoidance of concentrated acids, microbial cultures, and enzymes.Processes using hot compressed water may have two distinct operations:pre-treatment and cellulose hydrolysis. The pre-treatment processhydrolyzes the hemicellulose component of the lignocellulosic biomassand cellulose hydrolysis (CH) process, as its name infers, hydrolyzesthe cellulose fibers. The resultant five carbon (C5) and six carbon (C6)sugar streams are recovered separately. The remaining solids, whichconsist mostly of lignin, are preferably recovered, such as throughfiltration, and may be used as a fuel to provide thermal energy to theprocess itself or for other processes.

Among their many uses, the sugar streams may be converted to ethanolthrough fermentation using yeast or bacteria that feed on the sugars. Asthe sugars are consumed, ethanol and carbon dioxide are produced.

The invention is directed to these compositions, as well as and otherimportant ends.

SUMMARY OF THE INVENTION

In a first embodiment, the invention is directed to compositions,comprising C6 monosaccharides. In particular, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 6750 ppm in total by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate;

less than about 10 ppm by weight, based on total weight of water-solubleC6 saccharide hydrolysate in said composition, of aluminum;

less than about 350 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium;

less than about 425 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of iron;and

less than about 4500 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 10 ppm by weight, based on total weight of water-solubleC6 saccharide hydrolysate in said composition, of aluminum.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 350 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 425 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of iron.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 4500 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur.

In other embodiments, the invention is directed to compositions,comprising C5 monosaccharides. In particular, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 1950 ppm in total by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate;

less than about 5 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of aluminum;

less than about 300 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium;

less than about 10 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of iron; and

less than about 1000 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 5 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of aluminum.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 300 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 10 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of iron.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 1000 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the invention is directed to methods of reducingthe level of enzyme required for enzymatically hydrolyzing firstwater-soluble C6 saccharides having an average degree of polymerizationto about 2 to about 15, preferably about 2 to about 10, and morepreferably about 2 to about 6, to second water-soluble C6 saccharideshaving a lower average degree of polymerization than said average degreeof polymerization of said first water-soluble C6 saccharides,comprising:

providing a hydrolysate comprising said first water-soluble C6saccharides and less than about 5250 ppm in total by weight, based ontotal weight of water-soluble C6 saccharide hydrolysate in saidcomposition, of elements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain embodiments, the invention is directed to methods of reducingthe level of enzyme required for enzymatically hydrolyzing firstwater-soluble C5 saccharides having an average degree of polymerizationto about 2 to about 28, preferably about 2 to about 15, more preferablyabout 2 to about 13, even more preferably about 2 to about 6, to secondwater-soluble C5 saccharides having a lower average degree ofpolymerization than said average degree of polymerization of said firstwater-soluble C5 saccharides, comprising:

providing a hydrolysate comprising said first water-soluble C5saccharides and less than about 3700 ppm in total by weight, based ontotal weight of water-soluble C5 saccharide hydrolysate in saidcomposition, of elements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

DETAILED DESCRIPTION OF THE INVENTION

As employed above and throughout the disclosure, the following terms,unless otherwise indicated, shall be understood to have the followingmeanings.

As used herein, the singular forms “a,” “an,” and “the” include theplural reference unless the context clearly indicates otherwise.

While the present invention is capable of being embodied in variousforms, the description below of several embodiments is made with theunderstanding that the present disclosure is to be considered as anexemplification of the invention, and is not intended to limit theinvention to the specific embodiments illustrated. Headings are providedfor convenience only and are not to be construed to limit the inventionin any manner. Embodiments illustrated under any heading may be combinedwith embodiments illustrated under any other heading.

The use of numerical values in the various quantitative values specifiedin this application, unless expressly indicated otherwise, are stated asapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about.” In this manner,slight variations from a stated value can be used to achievesubstantially the same results as the stated value. Also, the disclosureof ranges is intended as a continuous range including every valuebetween the minimum and maximum values recited as well as any rangesthat can be formed by such values. Also disclosed herein are any and allratios (and ranges of any such ratios) that can be formed by dividing arecited numeric value into any other recited numeric value. Accordingly,the skilled person will appreciate that many such ratios, ranges, andranges of ratios can be unambiguously derived from the numerical valuespresented herein and in all instances such ratios, ranges, and ranges ofratios represent various embodiments of the present invention.

As used herein, the phrase “substantially free” means have no more thanabout 1%, preferably less than about 0.5%, more preferably, less thanabout 0.1%, by weight of a component, based on the total weight of anycomposition containing the component.

A supercritical fluid is a fluid at a temperature above its criticaltemperature and at a pressure above its critical pressure. Asupercritical fluid exists at or above its “critical point,” the pointof highest temperature and pressure at which the liquid and vapor (gas)phases can exist in equilibrium with one another. Above criticalpressure and critical temperature, the distinction between liquid andgas phases disappears. A supercritical fluid possesses approximately thepenetration properties of a gas simultaneously with the solventproperties of a liquid. Accordingly, supercritical fluid extraction hasthe benefit of high penetrability and good solvation.

Reported critical temperatures and pressures include: for pure water, acritical temperature of about 374.2° C., and a critical pressure ofabout 221 bar; for carbon dioxide, a critical temperature of about 31°C. and a critical pressure of about 72.9 atmospheres (about 1072 psig).Near critical water has a temperature at or above about 300° C. andbelow the critical temperature of water (374.2° C.), and a pressure highenough to ensure that all fluid is in the liquid phase. Sub-criticalwater has a temperature of less than about 300° C. and a pressure highenough to ensure that all fluid is in the liquid phase. Sub-criticalwater temperature may be greater than about 250° C. and less than about300° C., and in many instances sub-critical water has a temperaturebetween about 250° C. and about 280° C. The term “hot compressed water”is used interchangeably herein for water that is at or above itscritical state, or defined herein as near-critical or sub-critical, orany other temperature above about 50° C. (preferably, at least about100° C.) but less than subcritical and at pressures such that water isin a liquid state

As used herein, a fluid which is “supercritical” (e.g. supercriticalwater, supercritical CO₂, etc.) indicates a fluid which would besupercritical if present in pure form under a given set of temperatureand pressure conditions. For example, “supercritical water” indicateswater present at a temperature of at least about 374.2° C. and apressure of at least about 221 bar, whether the water is pure water, orpresent as a mixture (e.g. water and ethanol, water and CO₂, etc). Thus,for example, “a mixture of sub-critical water and supercritical carbondioxide” indicates a mixture of water and carbon dioxide at atemperature and pressure above that of the critical point for carbondioxide but below the critical point for water, regardless of whetherthe supercritical phase contains water and regardless of whether thewater phase contains any carbon dioxide. For example, a mixture ofsub-critical water and supercritical CO₂ may have a temperature of about250° C. to about 280° C. and a pressure of at least about 225 bar.

As used herein, “lignocellulosic biomass or a component part thereof”refers to plant biomass containing cellulose, hemicellulose, and ligninfrom a variety of sources, including, without limitation (1)agricultural residues (including corn stover and sugarcane bagasse), (2)dedicated energy crops, (3) wood residues (including hardwoods,softwoods, sawmill and paper mill discards), and (4) municipal waste,and their constituent parts including without limitation, lignocellulosebiomass itself, lignin, saccharides (including cellulose, cellobiose, C₆oligosaccharides, C₆ monosaccharides, C₆ saccharides (includinghemicellulose, C₆ oligosaccharides, and C₆ monosaccharides), andmixtures thereof.

As used herein, “ash” refers to the non-aqueous residue that remainsafter a sample is burned, and consists mostly of metal oxides. Ashcontent may be measured in accordance with ASTM Standard Method No.E1755-01 “Standard Method for the Determination of Ash in Biomass.” Thistest method covers the determination of ash, expressed as the percentageof residue remaining after dry oxidation at 550 to 600° C. All resultsare reported relative to the 105° C. oven dry weight of the sample. Seealso: Sluiter, A. et al., “Determination of Ash in Biomass,” NationalRenewable Energy Laboratory (NREL) Technical Report NREL/TP-510-42622,Jul. 17, 2005; and ASTM Standard Method No. E1755-01 “Standard Methodfor the Determination of Ash in Biomass,” 2007, which are bothincorporated herein by reference in their entirety.

As used herein, “degree of polymerization” refers to the number ofmonomeric units in a macromolecule or polymer or oligomer molecule,including those monomeric units that are not identical (such as in aoligomer with different monomeric residues). The degree ofpolymerization (DP) of the various saccharides in the compositions ofthe invention may be measured using gel permeation chromatography (GPC),high pressure liquid chromatography (HPLC), such as DIONEX with anelectrochemical detector, matrix-assisted laser desorption/ionizationtime-of-flight (MALDI-TOF) mass spectrometry, or other conventionalmolecular weight determination methods.

C6 Monosaccharides

Accordingly, in one embodiment, the invention is directed tocompositions, comprising C6 monosaccharides. In particular embodiments,the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 6750 ppm in total by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain preferred embodiments, said elements are present at a levelof less than about 6600 ppm in total by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of saidelements.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate;

less than about 10 ppm by weight, based on total weight of water-solubleC6 saccharide hydrolysate in said composition, of aluminum;

less than about 350 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium;

less than about 425 mg, based on total weight of water-soluble C6saccharide hydrolysate in said composition, of iron; and

less than about 4500 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 10 ppm by weight, based on total weight of water-solubleC6 saccharide hydrolysate in said composition, of aluminum.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 350 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 425 mg, based on total weight of water-soluble C6saccharide hydrolysate in said composition, of iron.

In certain embodiments, the compositions comprise:

at least one water-soluble C6 monosaccharide hydrolysate; and

less than about 4500 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions comprise:

less than about 6750 ppm in total by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain preferred embodiments, said elements are present at a levelof less than about 6600 ppm in total by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of saidelements.

In certain embodiments, the water-soluble C6 monosaccharide hydrolysateis extracted from lignocellulosic biomass. In certain embodiments, thewater-soluble C6 monosaccharide hydrolysate is processed fromlignocellulosic biomass using supercritical, subcritical, or nearcritical fluid extraction, or a combination thereof.

In certain embodiments, the compositions further comprise water.

In certain embodiments, the water-soluble C6 monosaccharide hydrolysateis present at a concentration of at least about 0.5 g/L.

In certain embodiments, the C6 monosaccharide is glucose, galactose,mannose, fructose, or a mixture thereof.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise less than about 10 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, ofaluminum, preferably less than about 7.5 ppm by weight, based on totalweight of water-soluble C6 saccharide hydrolysate in said composition,of aluminum.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise less than about 350 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium,preferably less than about 325 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of calcium.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise less than about 425 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of iron,preferably less than about 420 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of iron.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise less than about 4500 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur,preferably less than about 4425 ppm by weight, based on total weight ofwater-soluble C6 saccharide hydrolysate in said composition, of sulfur.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the weight ratio of saidwater-soluble C6 monosaccharide hydrolysate to said elements is greaterthan about 25:1, preferably greater than about 30:1.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise at least one water-soluble C6 oligosaccharide having a degreeof polymerization of about 2 to about 15, preferably about 2 to about13, more preferably about 2 to about 10, and even more preferably about2 to 6.

In certain preferred embodiments of the compositions comprising thewater-soluble C6 monosaccharide hydrolysate, the compositions furthercomprise at least one water-soluble C5 saccharide having a degree ofpolymerization of about 1 to about 28, preferably about 1 to 15, morepreferably about 1 to about 10, and even more preferably about 1 toabout 6.

In certain embodiments, the water-soluble C6 monosaccharide hydrolysateis processed from lignocellulosic biomass using supercritical,subcritical, or near critical fluid extraction, or a combinationthereof.

In certain embodiments, the level of said elements are measured byinductively coupled plasma emission spectroscopy.

In other embodiments, the compositions comprise less than about 1500 mgof nitrogen per kg of total weight of water-soluble C6 saccharides,preferably less than about 1450 mg of nitrogen per kg of total weight ofwater-soluble C6 saccharides. Nitrogen may be measured by thermalconductivity detection after combustion and reduction.

In yet other embodiments, the compositions further comprise a weightratio of the total mass of hydrogen and nitrogen to carbon of less thanabout 0.17.

In certain other embodiments, the compositions comprising the C6monosaccharides further comprise less than a maximum of any of theelements, individually or in combination, in the table listed below:

Level less than about (ppm or mg of element/kg Element of C6saccharides) As 0.25 B 1.0 Ba 1.0 Be 0.1 Cd 0.1 Co 0.25 Cr 3.25 Cu 325 K350 Li 25 Mg 0.1 Mn 625 Mo 3.0 Na 15 Ni 0.25 P 0.25 Pb 0.35 Sb 0.25 Se2.0 Si 0.1 Sn 0.3 Sr 0.1 Ti 0.25 Tl 1.0 V 1.0 Zn 0.1

C5 Monosaccharides

Accordingly, in one embodiment, the invention is directed tocompositions, comprising C5 monosaccharides. In particular, thecompositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 1950 ppm in total by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain preferred embodiments, the elements are present at a level ofless than about 1925 ppm in total by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate;

less than about 5 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of aluminum;

less than about 300 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium;

less than about 10 mg, based on total weight of water-soluble C5saccharide hydrolysate in said composition, of iron; and

less than about 1000 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 5 ppm by weight, based on total weight of water-solubleC5 saccharide hydrolysate in said composition, of aluminum.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 300 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 10 mg, based on total weight of water-soluble C5saccharide hydrolysate in said composition, of iron.

In certain embodiments, the compositions comprise:

at least one water-soluble C5 monosaccharide hydrolysate; and

less than about 1000 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur.

In certain embodiments, the compositions further comprise:

less than about 1950 ppm in total by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, ofelements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain preferred embodiments, the elements are present at a level ofless than about 1925 ppm in total by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise less than about 5 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, ofaluminum, preferably less than about 2 ppm by weight, based on totalweight of water-soluble C5 saccharide hydrolysate in said composition,of aluminum.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise less than about 300 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium,preferably less than about 280 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of calcium.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise less than about 10 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of iron,preferably less than about 5 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of iron.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise less than about 1000 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur,preferably less than about 975 ppm by weight, based on total weight ofwater-soluble C5 saccharide hydrolysate in said composition, of sulfur.

In certain preferred embodiments, the weight ratio of said C5monosaccharide to said elements is greater than about 90:1, preferablygreater than about 95:1.

In certain embodiments, the compositions further comprise water.

In certain embodiments, the water-soluble C5 monosaccharide hydrolysateis present at a concentration of at least 0.5 g/L.

In certain embodiments, the C5 monosaccharide is xylose, arabinose,lyxose, ribose, or a mixture thereof.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise at least one water-soluble C5 oligosaccharide having a degreeof polymerization of about 2 to about 28, preferably about 2 to about15, more preferably about 2 to about 10, and even more preferably about2 to 6.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise at least one water-soluble C6 saccharide having a degree ofpolymerization of about 1 to about 15, preferably about 1 to 13, morepreferably about 1 to about 10, and even more preferably about 1 toabout 6.

In certain preferred embodiments of the compositions comprising thewater-soluble C5 monosaccharide hydrolysate, the compositions furthercomprise at least one water-soluble C6 saccharide having a degree ofpolymerization of about 1 to about 15, preferably about 1 to about 13,more preferably about 1 to about 10, and even more preferably about 1 to6.

In certain embodiments, the water-soluble C5 monosaccharide hydrolysateis processed from lignocellulosic biomass using supercritical,subcritical, or near critical fluid extraction, or a combinationthereof.

In certain embodiments, the level of said elements are measured byinductively coupled plasma emission spectroscopy.

In other embodiments, the compositions comprise less than about 350 mgof nitrogen per kg of total weight of water-soluble C5 saccharides,preferably less than about 325 mg of nitrogen per kg of total weight ofwater-soluble C5 saccharides. Nitrogen may be measured by thermalconductivity detection after combustion and reduction.

In yet other embodiments, the compositions further comprise a weightratio of the total mass of hydrogen and nitrogen to carbon of less thanabout 0.17. Carbon, hydrogen, and nitrogen levels may be measured bythermal conductivity detection after combustion and reduction.

In certain other embodiments, the compositions comprising the C5monosaccharides further comprise less than a maximum of any of theelements, individually or in combination, in the table listed below:

Level less than about (ppm or mg of element/kg Element of C5saccharides) As 0.2 B 1.0 Ba 0.25 Be 0.1 Cd 0.1 Co 0.1 Cr 0.1 Cu 275 K325 Li 75 Mg 0.2 Mn 35 Mo 0.25 Na 20 Ni 0.25 P 0.15 Pb 0.25 Sb 0.20 Se3.0 Si 0.1 Sn 0.25 Sr 0.1 Ti 4.0 Tl 0.25 V 1.25 Zn 0.25

Further Embodiments

In further embodiments, the compositions further comprise less thanabout 0.5% by weight, based on the total weight of said C5monosaccharides or C6 monosaccharides, of organic solvent, such asalcohols, including water miscible lower aliphatic C₁-C₄ alcohols (e.g.,methanol, ethanol, isopropanol, t-butanol). In preferred embodiments,the compositions contain less than about 0.1% by weight, based on thetotal weight of said of said C5 monosaccharides or C6 monosaccharides oforganic solvent. In more preferred embodiments, the compositions containsubstantially no organic solvent.

The compositions of the invention are preferably prepared from biomassby processes employing supercritical, subcritical, and/or near criticalwater, preferably without the addition of acid. The processes mayinclude pretreatment step or steps using supercritical or near criticalwater to separate the C5 sugars (monomers and/or oligomers) fromcellulose and lignin. In the pretreatment step, suitable temperaturesare about 130° C. to about 250° C., suitable pressures are about 4 barsto about 100 bars, and suitable residence times are about 0.5 minutes toabout 5 hours. The processes may also include a cellulose hydrolysisstep or steps using supercritical or near critical water to separate thecellulose (which may processed to form C6 monomeric and/or oligomericsugars) from the lignin. In the hydrolysis step(s), suitabletemperatures are about 250° C. to about 450° C., suitable pressures areabout 40 bars to about 260 bars, and suitable residence times are about0.1 seconds to about 3 minutes. The C5 monomers in the pretreatment stepare formed by autohydrolysis both from xylan directly and/or from C5oligomers. Similarly, the C6 monomers are formed in the supercriticalhydrolysis step directly from the cellulose and/or from C6 oligomers.The pretreatment step also produces small amounts of C6 sugars inoligomeric and/or monomeric form. The C5 and C6 oligomers may behydrolyzed to their respective monomers using acid, such as sulfuricacid. The compositions may be prepared in any suitable reactor,including, but not limited to, a tubular reactor, a digester (vertical,horizontal, or inclined), or the like. Suitable digesters include thedigester system described in U.S. Pat. No. 8,057,639, which include adigester and a steam explosion unit, the entire disclosure of which isincorporated by reference.

The compositions of the invention comprising C5 monosaccharides or C6monosaccharides may be utilized in a wide variety of applications, whereC5 and C6 sugars are conventionally utilized, including, but not limitedto, the production of various chemicals and fuels using fermentative,enzymatic, catalytic, and non-catalytic (e.g., thermal decomposition)processes. Such processes are useful for preparing feedstocks for thepreparation of the following non-exhaustive list:

fuels (such as gasoline, jet fuel, butanol, and the like);

chemicals (such as acetic acid, acetic anhydride, acetone, acrylic acid,adipic acid, benzene, ethanol, ethylene, ethylene glycol, ethyleneoxide, methanol, polypropylene, terephthalic acid, toluene, xylene,1,3-propanediol, 1,4-butanediol, and the like);

pharmaceuticals and foods (such as acetoin, alanine, arabitol, ascorbicacid, aspartic acid, citric acid, coumaric acid, fumaric acid, glycerol,glycine, kojic acid, lactic acid, lysine, malonic acid, proline,propionic acid, serine, sorbitol, succinic acid, threonine, xylitol,sugar acids (glucaric acid, gluconic acid, xylonic acids), and thelike);

specialty chemicals (such as acontic acid, glutamic acid, malic acid,oxalic acid, and the like);

textile applications (such as formic acid and the like); and

industrial intermediates (acetaldehyde, 3-hydroxypropionic acid,2,5-furan dicarboxylic acid, furfural, glutaric acid, itaconic acid,levulinic acid, and the like).

In certain embodiments, the invention is directed to methods of reducingthe level of enzyme required for enzymatically hydrolyzing firstwater-soluble C6 saccharides having an average degree of polymerizationto about 2 to about 15, preferably about 2 to about 10, and morepreferably about 2 to about 6, to second water-soluble C6 saccharideshaving a lower average degree of polymerization than said average degreeof polymerization of said first water-soluble C6 saccharides,comprising:

providing a hydrolysate comprising said first water-soluble C6saccharides and less than about 5250 ppm in total by weight, based ontotal weight of water-soluble C6 saccharide hydrolysate in saidcomposition, of elements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain embodiments, the C6 saccharides are extracted fromlignocellulosic biomass.In other embodiments, the C6 saccharides are processed fromlignocellulosic biomass using supercritical, subcritical, or nearcritical fluid extraction, or a combination thereof.

In certain embodiments, the invention is directed to methods of reducingthe level of enzyme required for enzymatically hydrolyzing firstwater-soluble C5 saccharides having an average degree of polymerizationto about 2 to about 28, preferably about 2 to about 15, more preferablyabout 2 to about 13, even more preferably about 2 to about 6, to secondwater-soluble C5 saccharides having a lower average degree ofpolymerization than said average degree of polymerization of said firstwater-soluble C5 saccharides, comprising:

providing a hydrolysate comprising said first water-soluble C5saccharides and less than about 3700 ppm in total by weight, based ontotal weight of water-soluble C5 saccharide hydrolysate in saidcomposition, of elements;

wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K,Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.

In certain embodiments, the C5 saccharides are extracted fromlignocellulosic biomass.

In other embodiments, the C5 saccharides are processed fromlignocellulosic biomass using supercritical, subcritical, or nearcritical fluid extraction, or a combination thereof.

The present invention is further defined in the following Examples, inwhich all parts and percentages are by weight, unless otherwise stated.It should be understood that these examples, while indicating preferredembodiments of the invention, are given by way of illustration only andare not to be construed as limiting in any manner. From the abovediscussion and these examples, one skilled in the art can ascertain theessential characteristics of this invention, and without departing fromthe spirit and scope thereof, can make various changes and modificationsof the invention to adapt it to various usages and conditions.

EXAMPLES Example 1 Preparation of Monosaccharide Compositions

The C5 monosaccharide and C6 monosaccharide compositions of theinvention were prepared using supercritical, subcritical, and nearcritical water extraction in a two stage process followed by acidhydrolysis. Particulate lignocellulosic biomass consisting of mixedhardwood chips of 140 mesh or less was mixed with water to form a slurry(about 20% by weight solids). The slurry was heated to a temperature ofabout 170-245° C. and then feed into a pretreatment reactor for about1-120 minutes under sufficient pressure to keep the water in the liquidphase. The pretreated slurry was then cooled to a temperature less thanabout 100° C. under little (less than about 10 bar) or no pressure. Thepretreated solids were then separated from the liquid stream using afilter press. Alternatively, the solids may be separated using acentrifugal filter pressor. The pretreated solids were then mixed withwater to form a slurry and the slurry was heated to a temperature ofabout 150-250° C. The slurry was then subjected to supercritical waterat about 374-600° C. in a hydrolysis reactor for about 0.05-10 secondsunder a pressure of about 230-300 bar. After exiting the hydrolysisreactor, the hydrolyzed slurry was quenched with water and then flashedto about ambient temperature and pressure to remove water. The ligninsolids were then separated from the liquid stream using a centrifugaldecanter and air dried.

The C5 oligosaccharides and the C6 oligosaccharides streams were firstconcentrated to about 200 g/L, adjusted to about pH 3-4 and filteredusing 0.45 micron filter.

Sulfuric acid (0.3%) was added to the C5 oligosaccharides and the C6oligosaccharides streams in a tubular reactor at a residence time ofabout 1 minute at about 200° C. to hydrolyze the oligosaccharides totheir respective monosaccharides. Alternatively, a batch autoclave at alower temperature or a continuously stirred agitated tank reactor may beused. The glucose was cleaned with over liming and had acetic acid at alevel of less than about 5 g/L. The xylose was cleaned by contacting itwith ion exchange resin and had acetic acid at a level of less thanabout 5 g/L.

Example 2 Analysis of Monosaccharide Compositions Using InductivelyCoupled Plasma

The dried compositions containing the C5 and C6 monosaccharides ofExample 1 were analyzed using inductively coupled plasma emissionspectroscopy. The results are shown in the table below:

Monosaccharide Monosaccharide (glucose sample) (xylose sample) g/literor ppm g/liter or ppm based on total C6 based on total C5 Speciessaccharides saccharides Al 7.40 0.39 As 0.18 0.12 B 0.81 0.91 Ba 0.780.16 Be 0.00 0.00 Ca 0.08 0.02 Cd 0.07 0.02 Co 0.18 0.04 Cr 3.09 0.08 Cu316.00 261.00 Fe 0.05 0.03 K 333.00 291.00 Li 19.50 60.00 Mg 0.03 0.12Mn 590.00 33.60 Mo 2.09 0.18 Na 13.50 17.90 Ni 0.12 0.08 P 0.15 0.07 Pb0.24 0.16 S 54.50 10.80 Sb 0.20 0.14 Se 1.61 2.48 Si 0.00 0.00 Sn 0.240.16 Sr 0.00 0.00 Ti 88.90 3.56 Tl 0.18 0.12 V 0.81 0.91 Zn 0.78 0.16

When ranges are used herein for physical properties, such as molecularweight, or chemical properties, such as chemical formulae, allcombinations, and subcombinations of ranges specific embodiments thereinare intended to be included.

The disclosures of each patent, patent application, and publicationcited or described in this document are hereby incorporated herein byreference, in their entirety.

Those skilled in the art will appreciate that numerous changes andmodifications can be made to the preferred embodiments of the inventionand that such changes and modifications can be made without departingfrom the spirit of the invention. It is, therefore, intended that theappended claims cover all such equivalent variations as fall within thetrue spirit and scope of the invention.

What is claimed is:
 1. A composition, comprising: at least onewater-soluble C6 monosaccharide hydrolysate; at least one water-solubleC6 oligosaccharide hydrolysate having a degree of polymerization ofabout 2 to about 15; and impurities; wherein said impurities comprise:less than about 6750 ppm in total by weight of elements; wherein saidelements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn,Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.
 2. Thecomposition of claim 1, wherein said water-soluble C6 monosaccharidehydrolysate is extracted from lignocellulosic biomass.
 3. Thecomposition of claim 2, wherein said water-soluble C6 monosaccharidehydrolysate is processed from lignocellulosic biomass usingsupercritical, subcritical, or near critical fluid extraction, or acombination thereof.
 4. The composition of claim 1, further comprising:water.
 5. The composition of claim 1, wherein said water-soluble C6monosaccharide hydrolysate is present at a concentration of at leastabout 0.5 g/L.
 6. The composition of claim 1, wherein said water-solubleC6 monosaccharide hydrolysate is glucose, galactose, mannose, fructose,or a mixture thereof.
 7. The composition of claim 1, further comprising:less than about 10 ppm by weight of aluminum.
 8. The composition ofclaim 1, further comprising: less than about 350 ppm by weight ofcalcium.
 9. The composition of claim 1, further comprising: less thanabout 425 ppm by weight of iron.
 10. The composition of claim 1, furthercomprising: less than about 4500 ppm by weight of sulfur.
 11. Thecomposition of claim 1, wherein the weight ratio of said water-solubleC6 monosaccharide hydrolysate to said elements is greater than about25:1.
 12. The composition of claim 1, wherein level of said elements aremeasured by inductively coupled plasma emission spectroscopy.
 13. Thecomposition of claim 1, further comprising: less than about 1500 mg ofnitrogen per kg of total weight of water-soluble C6 saccharidehydrolysate.
 14. The composition of claim 1, further comprising: aweight ratio of the total mass of hydrogen and nitrogen to carbon ofless than about 0.17.
 15. The composition of claim 1, furthercomprising: at least one water-soluble C5 saccharide having a degree ofpolymerization of about 1 to about
 15. 16. A composition, comprising: atleast one water-soluble C6 monosaccharide hydrolysate; at least onewater-soluble C6 oligosaccharide hydrolysate having a degree ofpolymerization of about 2 to about 15; and impurities; wherein saidimpurities comprise: less than about 10 ppm by weight of aluminum. 17.The composition of claim 16, further comprising: less than about 425 ppmof iron.
 18. The composition of claim 17, further comprising: less thanabout 4500 ppm by weight of sulfur.
 19. The composition of claim 18,further comprising: less than about 350 ppm by weight of calcium. 20.The composition of claim 16, further comprising: less than about 6750ppm in total by weight of elements; wherein said elements are Al, As, B,Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb,Se, Si, Sn, Sr, Ti, Tl, V, and Zn.
 21. The composition of claim 16,further comprising: at least one water-soluble C5 saccharide having adegree of polymerization of about 1 to about
 15. 22. A composition,comprising: at least one water-soluble C6 monosaccharide hydrolysate; atleast one water-soluble C6 oligosaccharide hydrolysate having a degreeof polymerization of about 2 to about 15; and impurities; wherein saidimpurities comprise: less than about 350 ppm by weight of calcium.
 23. Acomposition, comprising: at least one water-soluble C6 monosaccharidehydrolysate; at least one water-soluble C6 oligosaccharide hydrolysatehaving a degree of polymerization of about 2 to about 15; andimpurities; wherein said impurities comprise: less than about 425 ppm ofiron.
 24. The composition of claim 23, further comprising: less thanabout 4500 ppm by weight of sulfur.
 25. The composition of claim 23,further comprising: less than about 6750 ppm in total by weight ofelements; wherein said elements are Al, As, B, Ba, Be, Ca, Cd, Co, Cr,Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl,V, and Zn.
 26. The composition of claim 23, further comprising: at leastone water-soluble C5 saccharide having a degree of polymerization ofabout 1 to about
 15. 27. A composition, comprising: at least onewater-soluble C6 monosaccharide hydrolysate; at least one water-solubleC6 oligosaccharide hydrolysate having a degree of polymerization ofabout 2 to about 15; and impurities; wherein said impurities comprise:less than about 4500 ppm by weight of sulfur.
 28. The composition ofclaim 27, further comprising: less than about 10 ppm by weight ofaluminum.
 29. The composition of claim 27, further comprising: less thanabout 6750 ppm in total by weight of elements; wherein said elements areAl, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P,Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn.
 30. The composition ofclaim 27, further comprising: at least one water-soluble C5 saccharidehaving a degree of polymerization of about 1 to about 15.